Herbicidal composition and method



United States Patent Ofilice 3,373,010 Patented Mar. 12, 1968 3,373,010HERBICIDAL COMPOSITION AND METHOD Harold C. Olson, Wilmington, Del.,assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., acorporation of Delaware No Drawing. Filed Oct. 8, 1964, Ser. No. 402,6084 Claims. (Cl. 71-120) ABSTRACT OF THE DISCLOSURE Compositionscontaining an herbicidally effective amount of1-(p-chlorophenyl)-3,3-dimethylurea, 1-(3,4- dichlorophenyl) 3,3dimethylurea or 1-(3,4-dichlorophenyl)-3-n-butyl-3-methylurea incombination with an herbicidally effective amount ofalpha,alpha,alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine andmethod of using same for synergistic herbicidal response.

This invention relates to herbicidal compositions. It is moreparticularly directed to compositions containing herbicidally effectiveamounts of:

A substituted urea selected from the group consisting ofl-(p-chloropheny)-3,3-dimethylurea, hereinafter referred to as monuron,1-(3,4-dichlorophenyl)-3,3-dimethylurea, hereinafter referred to asdiuron, and 3-(3,4- dichlorophenyl)-1-n-butyl-1-methylurea, hereinafterreferred to as neburon; and

Alpha,alpha,alpha-trifluoro 2,6 dinitro-N,N-dipropyl-p-toluidine,hereinafter referred to as trifluralin.

I have found it is characteristic of mixtures of the above namedsubstituted ureas with trifluralin to produce combinations which aremore effective as weed killers than either herbicide used alone. Theresult is that the combination has enhanced herbicidal effectiveness inthe destruction and prevention of weeds.

The ratio of substituted urea: trifiuralin can range from about 1:2 to5:1. Preferably the ratio is from 1:2 to 2: 1.

It is much preferred to formulate the active components of theinvention, comprising trifiuralin and one of the herbicidal substitutedphenyl ureas, with conventional pest control adjuvants, modifiers ordiluents, hereinafter called inert carriers. Formulation with such inertcarriers is preferred because handling is facilitated and herbicidalaction is thereby frequently enhanced.

These compositions, whether solutions, emulsions, dispersions of theactive components in a liquid solvent or wettable powders, contain as aconditioning agent one or more surface-active agents in an amountsuflicient to render a given composition containing the active componentreadily dispersible in water or in oil. By the term surfaceactive agentit is understood that wetting agents, dispersing agents, suspendingagents and emulsifying agents are included.

Suitable surface-active agents can be anionic, cationic, and non-ionic,such as are set out, for example, in Detergents and Emulsifiers-1964Annual by J. W. Mc- Cutcheon, Inc.

Suitable surface-active agents for use in compositions of the presentinvention are: polyethylene glycol esters with fatty acids or etherswith fatty alcohols and fatty alkylol amide condensates, alkylarylsulfonates, fatty alcohol sulfates, dialkyl esters of sodiumsulfosuccinate, fatty acid esters of sodium isethionate, polyoxyethyleneethers and thioethers and long chain quaternary ammonium chlorides.

Among the more preferred surfactants are the anionic and non-ionic type.Among the anionic surface-active agents, preferred ones are alkali metalor amine salts of alkylbenzene sulfonic acids such as dodecylbenzenesulthe form of a spray will contain fonic acid, sodium lauryl sulfate,alkylnaphthalene sulfonates, sodium N-methyl-N-oleoyltaurate, oleic acidester of sodium isethionate, dioctyl sodium sulfosuccinate, sodiumdodecyldiphenoloxide disulfonate. Among the non-ionic compounds,preferred members are alkylphenoxy poly(ethyleneoxy) ethanols such asoctyl, nonyl or dodecylphenol adducts with ethylene: oxide;trimethylnonyl polyethylene glycol ethers, polyethylene oxide adducts offatty and rosin acids, long chain alkyl mercaptan adducts with ethyleneoxide.

Other preferred surfactants include lignin sulfonates, sodium andcalcium salts of polymerized alkylnaphthalene sulfonates andalkylarylsulfonates, methyl cellulose, and polyvinyl acetate.

In preparing these herbicidal compositions, surface active agents willgenerally be employed at concentrations of from about 1% to 10%, byWeight. Levels as high as 0.25 to 6 parts for each part of the totalherbicides present, however, give unusual and unexpected beneficialresults. Such compositions have a greater herbicidal effectiveness thancan be expected from a consideration of the activity of the componentsused separately.

Powdered or dust compositions of the invention, whether or not alsomodified with a surface-active agent, are prepared by mixing the activecompounds of the invention with finely-divided inert carriers. Suchcarriers are preferably talc, natural clays, synthetic fine silica orcalcium silicate, pyrophyllite, diatomaceous earth and flours such aswalnut shell, wheat, soya bean, redwood and cotton seed iiours. Otherinert solids which can be used are sulfur, calcium sulfate, and thelike, either in powder or granular form. The percentage, by Weight, ofactive components in the solid compositions will vary according to themanner in which the compositions are to be applied, but in general, willbe from about 0.1 to percent, by weight.

Herbicidal compositions can also be prepared by dispersing or dissolvingthe active components in an inert non-aqueous carrier. Aliphatic andaromatic hydrocarbons, for example, hydrocarbons of petroleum origin,are preferred as carriers.

Other carriers, used alone or in admixture with petroleum hydrocarbons,may be alcohols, glycols, aliphatic or aromatic ketones such ascyclohexanone, acetophenone, or methylisobutyl ketones, or amides suchas dimethylformamide. Carriers such as dimethyl sulfoxide, Cellosolve,and carbitol may be used. The amount of herbicide in such compositionscan range from 10 percent or less to 40 or even 50 percent by weight.

Adhesives such as gelatin and albumin, and resins such as rosin, alkydresins and the like, can also be used in the compositions to increasethe tenacity of deposits following application.

In general, the herbicidal compositions as applied in from about 0.2percent to 95 percent by Weight of the combined herbicidally activecomponents.

Compositions of this invention various ways as follows:

Wettable powders are prepared by combining in a blender the two activecomponents in the desired ratio, adding a diluent together with awetting agent to :assure easy preparation of an aqueous suspension andalso a dispersing agent to prevent flocculation in water. Thesecomponents are blended together, then passed through a hammer mill orother suitable grinding device until the particle size is substantiallybelow 50 microns. The product is then reblended until homogenous.

Aqueous dispersions are prepared by mixing the active components, adispersing agent and a suspending agent with water and grinding in apebble mill or sand mill can be prepared in 3 until the individualparticles are substantially all below 5 microns.

Oil dispersions are prepared in substantially the same Way as aqueousdispersions, but in this case the dispersing agent chosen can also be anemulsifier for the oil so that the final product can be diluted withwater to form a spray emulsion. In these dispersions the trifluralin maybe partially or completely soluble. Emulsifiable oil solutions, in whichboth the substituted urea and trifluralin are soluble, are prepared bymixing the active components with solvents such as xylene, heavyaromatic naphtha or water insoluble ketones such as isophorone. Theaddition of an emulsifying agent to the solvent completes theformulation and also aid in the solution process. Such solutions maycontain -50% of active ingredient, 2l5% of emulsifier and 3588% solvent.

Pellets are prepared by blending the ground active ingredients with abinding clay, and if rapid disintegration in water is desired, also areadily soluble salt. The blend is then moistened with 10 to percentwater, and then extruded from a die under high pressure to yield acompact pellet. Such pellets may contain 3 to 50% by weight of activeingredient, and up to about 15% by weight of a soluble salt.

Granules are prepared by spraying an aqueous suspension of theherbicidal urea and an oil solution of trifluralin upon a granulardiluent such as granular attapulgite, while tumbling the latter toobtain uniform deposition. Alternatively, granules may also be preparedfrom mixtures such as described for pellets above, by mixing with largeramounts of water and forming in a commercial granulator such as theStokes granulator and drying the product.

Dusts are most frequently prepared by diluting wettable powders with adense, rapid settling diluent such as micaceous talc by blending the twotogether in a ribbon or cone blender. Alternatively, where wetting ordispersing agents are undesirable, the active components are first mixedwith a minor amount of a fluffing diluent and a grinding aid,micropulverized and then blended with the dense major diluent.

The herbicidal composition can be applied as a spray, dust or granule tothe locus or area to be protected from weeds. Such application can bemade directly upon the locus or area and the weeds thereon during theperiod of weed infestation in order to destroy the weeds, oralternatively, the application can be made in advance of an anticipatedweed infestation to prevent such infestation. Thus, the compositions canbe applied as foliar sprays, but can also be applied as sprays or asgranules or pellets directly to the soil. Alternatively, the drypowdered compositions can be dusted directly on the plants or on thesoil. For some purposes, as in the treatment of ponds or lake bottoms,it will be convenient to use the pellet formof the compositions.

The compositions of the invention are, of course, :ap' plied in amountsufficient to exert the desired herbicidal action. The rate ofapplication for destroying or preventing weeds will vary with theparticular weed pest involved, the formulation used, the herbicidalactivity of the active ingredients, the purposes for which theapplication is being made (such :as for either short-term or long-termcontrol), the manner of application, plant density, prevailing weatherconditions and like variables. Since many variables play a role, it isnot possible to indicate one rate of application suitable for allsituations.

In general, however, the rate of application of active components of theinvention when mixed with each other in the proportions above-indicatedand formulated with inert carriers will range from about 0.5 to 6 poundsper acre of active components. When the compositions are used forpre-emergence purposes the amount of urea used will range from about 0.3to 3.0 pounds per acre and the amount of trifluralin applied will rangefrom about 0.3 to 1.5 pounds per acre.

For some specific uses, specific combinations of this inventiondemonstrate greatly enhanced herbicidal effectiveness. Rates ofapplication that are generally found effective in these situations canbe indicated, but it must be remembered that the determination of theproper rate in any given instance is conventional procedure to thoseskilled in the art. Thus, for example, the combination of diuron withtrifluralin is outstandingly useful in controlling a wide variety ofweeds in cotton. For instance, weeds such as crabgrass, Digitaria spp.;foxtail, Setaria spp.; barnyardgrass, Ec/rs'nochloa crusgalli; seedlingJohnsongrass, Sorghum halepense; pigweed, Amaranthus spp.; goosegrass,Eleusine indica; ragweed, Ambrosia spp.; annual morningglory Ipomoeaspp.; and cocklebur, Xanthium spp.; are controlled in cotton whensprayed with the combination of diuron and trifluralin.

Combinations of monuron and trifluralin are suitable for use incontrolling weeds in cotton, sugar cane, and citrus orchards andneburon-trifiuralin combinations are particularly suited for controllingweeds in nursery stock.

These combinations can be applied to the weed-infested area such as byspraying. Immediately after application, the soil can be disked as witha rototiller. The crop can be planted at that time or two to three weekslater, depending on application rates, and the control of weeds isexcellent.

Pre-emergence application and directed post-emergence treatments otherthan by spraying, using these compositions, are also useful to killweeds in agricultural crop fields. Rates of application in pre-emergenceuse depend upon the desired effect. For example, rates of applicationranging from about 0.3 to 3.0 pounds per acre of herbicidal urea andabout 0.3 to 1.5 pounds per acre of trifiuralin are generally sufficientfor pre-emergence application.

In order that the invention can be better understood the followingexamples are given in addition to the ex- 21 .iples already given above.The examples illustrate typical herbicidal compositions of theinvention, methods for their preparation, herbicidal applications andresults obtained. The numbers following the tabulated ingredientsrepresent parts by weight of the ingredients within the respectivecompositions.

Example I A tank mix in gallons of water is applied at the rate of 0.75pound of active ingredient per acre of both 3-(3,4-dichlorophenyl)-l,ldimethylurea as K armex wettable powder diuron) anda,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine as Treflan EC 44.5%trifluralin, to a cotton field which has not yet been planted. The soilis a clay loam. Immediately after spraying, the chemical treatment isincorporated into the soil to a depth of 1 to 2 inches by means of arototiller. The cotton seed is planted within two weeks at a depth of 1%inches. For 7 to 12 weeks, and sometimes longer, the herbicideapplication provides effective control of crabgrass, goosegrass,foxtail, ragweed, pigweed and annual morningglory.

Example 11 A tank mixture of the two compounds of Example I in 40gallons of water is utilized at the rate of 0.4 to 0.6 pound of activeingredient per acre, of each of the two active ingredients along with2.0 pounds of trimethylnonyl polyethylene glycol ether, on a cottonfield which is in the process of being planted. Application is made bymeans of tractor-mounted equipment in such a manner that the herbicidalmixture is immediately disced into the soil to a depth of l to 2 inches.The cotton is planted at a depth of 1%. inches. The treatment providesexcellent control for an extended period on such weed species ascrabgrass, Johnsongrass seedlings, harnyardgrass, foxtail, cocklebur,velvetleaf and annual morningglory.

Example III The tank mixture of Example 2 is used at the same rates forpre-emergence control of the annual weeds, listed in Example 2 insoybeans. The soybeans are planted 1% inches deep. Shortly thereafterthe mixture is applied at the rates of Example 2. Within a few minutesthe compounds are incorporated to a depth of /2 to 1 inch. Excellent'weed control is observed.

Example IV Example V Percent Diuron 20 Trifluralin 20 Dioctyl sodiumsulfosuccinate 2 Sodium lignin sulfonate 3 Attapulgite clay 55 Awettable powder is prepared in the following manner. The aboveingredients are blended and ground to a particle size smaller than 30mesh. This product is then micropulverized in an air mill to a particlesize below 50 microns. The mixture is reblended and is then ready foruse as a wettable powder.

Example VI Percent Monuron 50 Trifluralin 1O Alkylaryl sodium sulfonate2 Methyl cellulose 1 Attapulgite clay 37 The above ingredients areformulated as a wettable powder by blending and micropulverizing to aparticle size below 50 microns, followed by reblending.

Example VII Percent Neburon Trifluralin 20 Alkylaryl calcium sulfonate30 Trimethylnonyl polyethylene glycol ether 3 Xylenes 46 An emulsifiablesolution is prepared by stirring the above components in a tank until ahomogenous solution is obtained.

Example VIII Percent 50% active neburon wetta-ble powder 10 44.5% activetrifluralin emulsifiable 1O Granular attaclay (IS-30 mesh) 80 Thegranular attaclay is tumbled in a mixer to which the neburon wettablepowder is added. This agitated mix is sprayed with the trifiuralindiluted 1:1 with xylene. After the spraying is complete, excess solventis removed by drying and the granules are ready for application.

Example IX Percent Diuron Trifluralin 5 Hydrated attapulgite clay 79Nonylphenylpolyethylene glycol ether 1 The above components are blended,micropulverized to pass a 30 mesh screen and moist granulated in aStoker granulator by addition of 15-20% of water. The granules are driedand are then ready for application.

The above components are blended, micropulverized to pass a 30 meshscreen, moistened with 15-20% of water acid extruded under pressurethrough a die. The extrusions are cut into pellets and dried prior toapplication.

Example XI Percent Diuron 15 Trifluralin n 10 Hydrated attapulgite clay2 Disodium hydrogen phosphate anhydrous 1 Calcium magnesium ligninsulfonate 15 Sodium pentachlorophenate 1 Water 56 An aqueous dispersionis prepared by grinding the above dry components to pass a 30 meshscreen. The water is then added and the aqueous suspension is ground ina sand mill with external cooling to a particle size essentially lessthan 5 microns.

Example XII Percent Monuron l 20 'Iln'fluralin 10 White mineral oil 60Polyoxyethylene sorbital hexa-oleate 10 An oil dispersion is prepared bygrinding the above dry Example XIII A tank mix in 75 gallons of water isapplied at a rate of 0.75 pound of active ingredient per acre of both1-(pchlorophenyl)-3,3-dimethylurea as Telvar wettable powder, monuronand a,a,a-trifiuoro-2,6-dinitro-N,

-dipropyl-p-toluidine as Treflan EC 44.5% trifluralin, to a cotton fieldwhich has not yet been planted. The manner and depth of application arethe same as in Example I, and similar outstanding results are obtained.

The embodiments of the invention in which an exclusive property orprivilege is claimed are:

1. A herbicidal composition comprising a herbicidally effective amountof a mixture of:

a substituted urea selected from the group consisting of 1 (3,4dichlorophenyl)-3,3-dimethylurea, l-(pchlorophenyl)-3,3-dimethylurea and1-(3,4-dichlorophenyl)-3-n-butyl-3-methylurea; and

a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine; the ratio of11,,06 trifluoro 2,6-dinitro-N,N-dipropyl-ptoluidine: substituted ureabeing from 1:0.5 to 122.0.

2. A herbicidal composition comprising a herbicidally effective amountof a mixture of one part by Weight of ot,ot,ot trifluoro2,6-dinitro-N,N-dipropyl-p-toluidine and 0.5 to 2.0 parts by weight of1-(3,4-dichlorophenyl)-3,3- dirnethylurea.

3. A method for the control of weeds which comprises applying to a locusto be protected a herbicidal composition comprising a herbicidallyefifective amount of a mixture of:

a substituted urea selected from the group consisting of 1(3,4dich1oropheny1)-3,3-dimethylurea, l-(p-chloropheny1)-3,3dimethylurea and 1 (3,4 dichlorophenyl)-3-n-=buty1-3-methyl*urea; anda,a,a-trifiuoro2,G-dinitro-N,N-dipropyl-p-toluidine, the ratio of a,u,octrifl'uoro 2,6-dinitro-N,N-dipropylptoluidine: substituted urea beingfrom 1:05 to 1:2.0.

4. A method for the control of Weeds which comprises applying to a locusto be protected a herbicidal composition comprising a herbicidallyeffective amount of a mixture of one part by weight of0c,a,oc-tl'iflllOrO-2,6-di11itl0 8 N,N-dipropyi-p-toluidine and 0.5 to2.0 parts by weight of 1-(3,4-di:hloropheny1) -3,3-dimethy1urea.

References Cited 5 UNITED STATES PATENTS 2,709,648 5/1955 Ryker et a1.712.6 3,257,190 6/1966 Soper 71 2.3

10 JAMES O. THOMAS, 111., Primary Examiner.

